[C# 關鍵字 | Microsoft Learn](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/) [abstract](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/abstract) [as](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/type-testing-and-cast#as-operator) [base](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/base) [bool](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/bool) [break](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/jump-statements#the-break-statement) [byte](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/integral-numeric-types) [case](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/selection-statements#the-switch-statement) [catch](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/try-catch) [char](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/char) [checked](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/checked) [class](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/class) [const](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/const) [continue](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/jump-statements#the-continue-statement) [decimal](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/floating-point-numeric-types) [default](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/default) [delegate](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/reference-types) [do](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/iteration-statements#the-do-statement) [double](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/floating-point-numeric-types) [else](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/selection-statements#the-if-statement) [enum](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/enum) [event](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/event) [explicit](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/user-defined-conversion-operators) [extern](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/extern) [false](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/bool) [finally](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/try-finally) [fixed](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/fixed-statement) [float](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/floating-point-numeric-types) [for](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/iteration-statements#the-for-statement) [foreach](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/iteration-statements#the-foreach-statement) [goto](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/jump-statements#the-goto-statement) [if](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/selection-statements#the-if-statement) [implicit](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/user-defined-conversion-operators) [in](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/in) [int](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/integral-numeric-types) [interface](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/interface) [internal](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/internal) [is](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/is) [lock](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/lock) [long](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/integral-numeric-types) [namespace](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/namespace) [new](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/new-operator) [null](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/null) [object](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/reference-types) [operator](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/operator-overloading) [out](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/out) [override](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/override) [params](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/params) [private](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/private) [protected](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/protected) [public](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/public) [readonly](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/readonly) [ref](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/ref) [return](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/jump-statements#the-return-statement) [sbyte](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/integral-numeric-types) [sealed](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/sealed) [short](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/integral-numeric-types) [sizeof](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/sizeof) [stackalloc](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/stackalloc) [static](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/static) [string](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/reference-types) [struct](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/struct) [switch](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/switch-expression) [this](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/this) [throw](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/throw) [true](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/bool) [try](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/try-catch) [typeof](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/type-testing-and-cast#typeof-operator) [uint](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/integral-numeric-types) [ulong](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/integral-numeric-types) [unchecked](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/unchecked) [unsafe](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/unsafe) [ushort](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/integral-numeric-types) [using](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/using) [virtual](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/virtual) [void](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/void) [volatile](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/volatile) [while](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/statements/iteration-statements#the-while-statement) [](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/#contextual-keywords) ## 上下文關鍵字 上下文關鍵字用于在代碼中提供特定含義，但它不是 C# 中的保留字。 一些上下文關鍵字（如`partial`和`where`）在兩個或多個上下文中有特殊含義。 [add](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/add) [and](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/patterns#logical-patterns) [alias](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/extern-alias) [ascending](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/ascending) [args](https://learn.microsoft.com/zh-cn/dotnet/csharp/fundamentals/program-structure/top-level-statements#args) [async](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/async) [await](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/await) [by](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/by) [descending](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/descending) [dynamic](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/reference-types) [equals](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/equals) [from](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/from-clause) [get](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/get) [global](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/namespace-alias-qualifier) [group](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/group-clause) [init](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/init) [into](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/into) [join](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/join-clause) [let](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/let-clause) [托管（函數指針調用約定）](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/unsafe-code#function-pointers) [nameof](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/nameof) [nint](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/integral-numeric-types) [not](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/patterns#logical-patterns) [notnull](https://learn.microsoft.com/zh-cn/dotnet/csharp/programming-guide/generics/constraints-on-type-parameters#notnull-constraint) [nuint](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/builtin-types/integral-numeric-types) [on](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/on) [or](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/patterns#logical-patterns) [orderby](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/orderby-clause) [partial（類型）](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/partial-type) [partial（方法）](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/partial-method) [record](https://learn.microsoft.com/zh-cn/dotnet/csharp/fundamentals/types/records) [remove](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/remove) [select](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/select-clause) [set](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/set) [非托管（函數指針調用約定）](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/unsafe-code#function-pointers) [unmanaged（泛型類型約束）](https://learn.microsoft.com/zh-cn/dotnet/csharp/programming-guide/generics/constraints-on-type-parameters#unmanaged-constraint) [value](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/value) [var](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/var) [when（篩選條件）](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/when) [where（泛型類型約束）](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/where-generic-type-constraint) [where（查詢子句）](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/where-clause) [with](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/operators/with-expression) [yield](https://learn.microsoft.com/zh-cn/dotnet/csharp/language-reference/keywords/yield)